Aqueous household detergent compositions have, for many years, employed bleaches for the purpose of bleaching and/or disinfecting hard-surfaces and/or fabrics. Hypochlorite bleaches have been used most extensively for this purpose because they are highly effective and inexpensive. A drawback associated with hypochlorite bleaches is that they are perceived by the consumer as being not fully satisfactory regarding their safety profile.
Aqueous compositions comprising a peroxygen bleach have generally been less utilised in the household market, although they deliver effective bleaching performance and/or disinfecting performance, and they are perceived by the consumer as being less harsh than compositions based on hypochlorite. For example, hydrogen peroxide is generally perceived to be environmentally acceptable as its decomposition products are oxygen and water. It is believed that this lack of use in the household is partially attributable to the instability of aqueous peroxygen bleach-containing compositions. This instability is particularly noticeable in alkaline medium where it is mediated principally by contamination of metal ion occurring in the composition itself and/or in the wash solution obtained after having diluted the composition with water.
Furthermore, although such aqueous peroxygen bleach-containing compositions provide effective bleaching and/or disinfecting, they do not effectively remove greasy stains. Thus, there is still some room to further improve the greasy stain removal performance of liquid aqueous peroxygen bleach based compositions.
It is thus an object of the present invention to provide liquid aqueous peroxygen bleach-containing compositions which are effective in removing greasy stains, which are chemically more stable, and which provide effective disinfecting performance.
It has now been found that these objects can be achieved by formulating liquid aqueous alkaline compositions having a pH above 8, comprising a peroxygen bleach, a radical scavenger, a chelating agent and a pH buffer.
Indeed, it has surprisingly been found that the combined use of a chelating agent preferably a phosphonate/amino phosphonate chelating agent, a radical scavenger, preferably di-tert-butyl hydroxy toluene (BHT) and/or butyl hydroxyanisol (BHA), and a pH buffer, preferably a borate pH buffer, in an alkaline aqueous peroxygen bleach-containing composition, maintains both the pH and the peroxygen bleach stability upon prolonged storage periods. Furthermore, it has now been found that by formulating such an aqueous peroxygen bleach-containing composition at a pH above 8, comprising a chelating agent, a radical scavenger and a pH buffer, improved greasy stain removal performance is delivered while providing effective disinfecting performance.
The compositions according to the present invention are suitable for use on all types of surfaces, including inanimate surfaces like hard-surfaces, fabrics, cloths, carpets and the like, as well as on animate surfaces like human skin, mouths and the like. Preferred applications of the compositions of the present invention are hard-surfaces applications and/or laundry applications, e.g., as a laundry detergent, a laundry additive, or even as a laundry pretreater. More particularly, an advantage of the compositions according to the present invention is that they are suitable to be used on delicate surfaces. Indeed, when using the compositions according to the present invention in a laundry application fabric damage and/or color damage is reduced as compared to the same compositions without said chelating agent and/or radical scavenger.
The aqueous compositions of the present invention may comprise an antimicrobial compound preferably an antimicrobial essential oil and/or active thereof, which further contributes to the disinfecting performance of the compositions. An advantage of such compositions is that they deliver effective disinfection on a broad range of bacterial strains including Gram positive and Gram negative bacterial strains but also more resistant microorganisms like fungi, this even at high dilution levels, e.g., up to dilution levels of from 1:100 (composition:water).
The aqueous compositions herein may also comprise at least one surfactant and/or at least one solvent which further contribute to the overall stain removal performance of said compositions.